Devices of the above-mentioned type are widely used in packing lines for confectionery products, such as bars of chocolate, biscuits or others of similar types, in which those products are moved on transport lines, for example, arranged in rows or groups of rows which are spaced apart from each other (the term “rows” is intended to be understood in the present context to be rows of aligned products in which the rows are arranged perpendicularly to the direction of advance of the products). There is typically interposed between those transport lines and the packing machines an accumulation unit for the products in order to allow a regular supply with a predetermined and uniform rate of the packing device, and thereby to make that supply independent of the speed and the variations of the flow of the rows arriving.
With those accumulation units, therefore, it is possible to efficiently supply different automatic packing lines having supply speeds and rates which are programmed in accordance with the type of products processed. Typically, those accumulation devices comprise a store, inside which there are supported and conveyed a plurality of container elements in series along a trajectory which optimizes the capacity of accumulation. Generally, the containers are regularly spaced apart from each other at a predetermined interval and each of them comprises a plurality of levels which are capable of supporting and containing respective rows of products. It is typical to provide one or more transport chains on which the containers are retained at a regular interval. The sliding trajectory of the chain is further selected in such a manner that each container is sequentially guided to the reception opening in order to load on each of the levels thereof one or more rows of products arriving at the accumulation unit and, at the same time, a previously loaded container is conveyed, by the effect of the movement of the chain, to the delivery opening in order to release the products being discharged from the accumulation unit.
Accumulation devices of this type provide for an ascending vertical portion of the chain in order to sequentially load the containers through the reception opening and a descending vertical portion of the chain in order to position the containers in the region of the delivery opening and to unload the products from the accumulation unit as a result.
An example of an accumulation device of the above-mentioned type is described in the European Patent No. 1608573.
A discernible limit in this type of accumulation devices involves the fact that a possible interruption during the discharge of products through the delivery opening from the accumulation unit, for example, as a result of breakdowns or maintenance operations on the line of the discharge transporters (so that it is necessary to stop the transporters downstream of the accumulation unit), involves the consequent interruption of the product supply to the packing machines which are positioned downstream of the accumulation unit, with obvious consequent disadvantages for the productivity of the overall installation. Only when it is possible to restart the system of discharge transporters which receive the products through the delivery opening of the accumulation unit, is it possible to take up again the regular rate of supply of the packing lines which are arranged downstream of the accumulation unit. Furthermore, in the case of temporary interruptions to the product discharge line from the accumulation unit, it is also possible to compromise the regularity and rate of supply of the products arriving at the accumulation unit. In this case, once the accumulation unit has become full, with all the containers inside it being full, it is necessary to stop the movement of the transporters which supply the accumulation unit, with obvious disadvantages for the efficiency and productivity of the devices of the installation arranged upstream of the accumulation unit.
The problem addressed by the present invention is to provide a device for the accumulation and release of products, which is structurally and functionally configured to allow the limitations set out with reference to the cited prior art to be overcome.